What is important in semiconductor device manufacturing processes is a technique for detecting non-confirming or defective articles in semiconductor devices and analyzes the causes. There are some inspection apparatuses used for detecting such defects; for example, inspection apparatuses for electrical characteristics of circuits, external view checking apparatuses for inspecting foreign matters existing in wiring patterns, improper shapes of wiring patterns, etc. In those inspection apparatuses, defects to be subjected to defect cause analysis are picked up first, then positional information of each specified defect on the subject specimen is sent to an analyzer, in which electrical characteristics, compositions, and cross sectional shapes of the specified defect are observed.
Usually, the position setting accuracy of a specimen stage used for each of such inspection apparatuses is several micrometers. In recent years, wiring patterns of semiconductor devices are formed very finely. For example, the size of a memory cell block of a memory device mass-produced in these days is about several hundreds of nanometers. Consequently, it is difficult to report coordinate information of a defect detected in an inspection apparatus to another with required accuracy only with the positional control information of the specimen stage of the inspection apparatus.
Each of wiring patterns and circuit patterns in many semiconductor devices has an array structure in which similarly structured cells are disposed regularly according to their design data. The design data can be used as CAD data in various measuring and inspection apparatuses. In case where a defect detected in an inspection apparatus is to be analyzed in any of various other analyzing apparatuses, in addition to the coordinate information of the defect obtained in the inspection apparatus, the information of the defect position on the design data is also obtained from the CAD data. Each of the analyzing apparatuses selects an appropriate reference position as a starting point on the subject specimen and executes matching with the reference position to know where is the reference position on the CAD data and how far the target position of the analysis is away from the reference position. Such a reference position is selected from, for example, an edge of an array structure of a semiconductor device. At this time, the analyzer counts the number of cells from a given starting point to an ending point up to reach the ending point. And pattern measurement (cell counting) is needed at this time to measure how often a predetermined pattern appears between the starting point and the ending point. In case where the number of patterns is comparatively less, the operator can count the number of patterns at a visual check. In the case of a device having several hundreds or several thousands of cells, it is strongly required to make pattern counting automatically.
JP-A No. 92883/10 discloses a technique for obtaining an image of a target position with use of an optical photograph, an electron microscope, or the like to count the number of memory cells on a memory LSI from changes of the brightness or luminosity of the image with use of a pattern recognition device. The pattern recognition device holds the ending point of cell counting as a physical address and ends the memory cell counting when the number of counted memory cells matches with the value indicated in the physical address. The pattern recognition device determines the counting ended position as a logical address, which is coordinates on the design plan of the memory LSI.
JP-A No. 251824/2000 discloses an invention in which the visual field of a SEM image is moved while stage moving vectors are detected in a range from a starting point of cell counting to a target point. When the stage moving distance reaches a predetermined electron beam deflection limit, the stage is stopped once. Then, the number of cells disposed in the visual field of the observation is extracted at that position. And according to the extracted data, a mutual positional relationship between a disposed cell and another is identified and the visual field of the SEM image is moved again. By repeating such movements in many steps, the specified cell is moved in the visual field of the SEM image. A specimen stage moving vector is obtained by specifying a cell as an index basic pattern and from a relative movement of the index basic pattern in the visual field of the SEM image before and after the specimen stage movement. The relative movement of the index basic pattern in the visual field of the SEM image is obtained from a differential image of the SEM images before and after the specimen stage movement.    [Patent document 1] JP-A No. 092883/10    [Patent document 2] JP-A No. 251824/2000